Excess flow check valve



United States Patent n|13,540,46 9,

II'W'EIIOE' DIV P e 1,112,911; 6ll96 4 Germany 131/493 [21 1 App]. No.802.474 i [22] Filed Feb, 26, 1969 Primary Examiner-M. Cary Nelson [45]Patented Nov. 17, 1910 Assistant Examiner-R. B. Rothman Atto'rney-Schley and Schley [s41 excrzssnow CHECK VALVE chh"1nnwh'm ABSTRACT:Excess flow check valve for liquefied gaseous 1 137/5134 fluid. such asliquefied petroleum gas and anhydrous am- 137/5 137/5" monia, handlingequipment and particularly for safeguarding [51] Int. the withdrawal ofsuch fluid from storage tanks. The valve has FIG twystage d re to ermitthe sue of weak mun 5 i spring, which is more sensitive and resilient,and a plurality of lateral ports, of relatively large area and minimumquantity. in

[56] cm its housing to separate the flow into smaller streams of suffiUNITED STATES PATENTS cient area to minimize turbulence and providesubstantially l,l53,770 9ll9l5 Daymon l37l5l2.l uniform closing of saidvalve irrespective of the flow area 2,926,046 2/l960 Blair.... l37/5l7Xthere-around. Preferably, the ports are of maximum dimen- 2,968.315lll96l Fisher 137/5 l 7 sions to permit maximum controlled flow.

Patented Nov. 17, 1970 I 'of 2 Sheet Patented Nov. 17, 1910 v 3,540,469

Sheet 2 of 2 I9 k 1m- /6 w 1? l 23 "Ill" Q 29 F I Q 4 INVENTOR.

David P. Word ATTORNEYS EXCESS FLOW CHECK VALVE BACKGROUND OF THEINVENTION The ever increasing demand for faster fluid transfer rates invarious industries, such as the handling of liquefied gaseous fluids,including but not limited to liquefied petroleum gas and anhydrousammonia, has made essential more efficient valves and fittings. Thesafety standards set by the governing bodies of these industries requirean excess flow check valve of the spring-pressed type at each flowopening, except gauge and relief valve, of a storage tank or othercontainer and, preferably. the check valve should be disposed within theinterior of the tank. In some flow openings, a collar or half-pipecoupling is secured to provide an unrestricted area within the tank orother container for the mounting of a check valve. Usually, the fluidfill and eduction opening of a storage tank has a fill and eduction pipeor dip tube depending therefrom through the vapor space to the bottom ofthe tank to permit removal of the gaseous fluid in liquefied conditionand this pipe or tube is suspended from the collar, a full pipe couplingor a special fitting having an enlarged interior portion. The generalusage of dip tubes results in wide variations in the areas 'of the flowspaced around the exteriors of the excess flow check valves.

Although so-called high flow" excess flow check valves have beenavailable for several years, most of said valves are ofthe single-valvedisk and seat type and have a comparatively high pressure drop acrosstheir seats during withdrawal as well as filling. One of the mostundesirable characteristic of this type of valve is the effect that diptubes, couplings and other fittings of different diameter, whichsurround the valve, have on the capacity of closing moment of saidvalve. The confinement of such a valve in a fitting of minimum diametercauses a much lower closing rate (gallons or cubic feet per minute) thanwhen the same valve is mounted in the open vapor space of a storage tankor within a fitting of larger or optimum diameter. Accordingly, the areaof the flow space immediately surrounding an excess flow check valve isa function of the capacity or closing moment of the valve or,conversely, said valve capacity or closing moment is a function of saidflow space area.

SUMMARY OF THE INVENTION This invention relates to a novel excess flowcheck valve for use in equipment for handling liquefied gaseous fluids,including but not limited to liquefied petroleum gas and anhydrousammonia, and more particularly to safeguard the withdrawal of suchfluids from a storage tank under vapor pressure in the tank. The checkvalve includes a valve assembly having a tubular member for engagementwith an annular seat and a circular element for engagement with thetubular member whereby a two-stage closure for shutting off flow isprovided to permit the use of an actuating spring ofless strength aswell as greater sensitivity and resiliency. A plurality of lateralports, of relatively large area and minimum quantity, is formed in thehousing of'the valve to separate the flow into smaller streams ofsufficient area to minimize turbulence and provide substantially uniformclosing of said valve, the moment of which closing is not affectedappreciably by the area of the flow space immediately surrounding saidvalve housing. The tubular valve member is reciprocal relative to thecircular valve ele ment and, in open position. is closer to the valveseat than to said element whereby said valve member engages said valveseat prior to being engaged by said valve element so as to reduce theflow area through the check valve. The portion of the valve housingadjacent the tubular valve member is enlarged to provide a flow spaceexternally of said valve member and has a number of its ports above oroutwardly of the open or unseated valve member to minimize restrictionof flow between the exterior and interior of said housing.

Due to the relatively large area and minimum quantity of the lateralports, substantially all of the circular valve element and at least aportion of the tubular valve member are exposed directly to the exteriorof the valve housing. Preferably, the lateral ports are of maximumdimensions, being formed by narrow legs extending longitudinally of thevalve housing, and are substantially coextensive with the length of saidvalve housing. Although it is preferable for the lateral ports to beformed by a first set of openings elongated circumferentially of thevalve housing between the valve seat and the unseated tubular valvemember and a second set of openings spaced from the first set innonoverlapping relationship and of maximum dimensions longitudinally andcircumferentially of said valve housing so as to be substantiallycoextensive with the travel of the circular valve element, said portsmay be formed by a single set of continuous openings so as to exposesubstantially all of said valve member as well as said valve elementdirectly to the exterior of said valve housing substantially throughoutthe travel ofsaid member and element.

A construction designed to carry out the invention will be hereinafterdescribed, together with other features of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a transverse, vertical,sectional view, partly in elevation, of a portion ofa storage tankhaving an excess flow check valve, in open position and constructed inaccordance with the invention, secured to the lower end of a fluid filland eduction control valve so as to depend into the upper end of aconventional dip tube,

'FIG. 2 is an enlarged, transverse, vertical, sectional view, partly inelevation, of the open check valve and adjacent portions of the diptube, control valve and tank,

FIG. 3 is a view, similar to FIG. 2, showing the check valve in closedposition,

FIG. 4 is an exploded, perspective view of the check valve,

FIG. 5 is a horizontal, cross-sectional view taken on the 5- 5 of FIG.2,

FIG. 6 is a horizontal, cross-sectional view taken on the line 6-6 ofFIG. 2, and

FIG. 7 is a side elevational view ofa slightly modified excess flowcheck valve.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings, the numeral 1designates a portion of a storage tank for liquefied gaseous fluids,such as liquefied petroleum gas and anhydrous ammonia, having aninternally screw-threaded collar or half-pipe coupling 2 secured in itsfluid inlet-outlet opening 3. A fluid fill and withdrawal pipe 4,commonly referred to as a dip tube, may be secured to the lower end ofthe collar 2 and extend to the bottom portion of the tank I in the usualmanner. The collar is adapted to support a liquid fill and eduction,manual control valve 5 which has its depending nipple 6 screw-threadedin the upper portion of said collar. An excess flow check valve 7,embodying the principles of the invention, is suspended from the controlvalve 5 so as to depend coaxially into the dip tube 4. Although diptubes are desirable and preferable, many storage tanks are not providedwith the same. In this event, the check valve need not be mountedvertically.

As best shown in FIGS. 2-4, the check valve 7 has a hollow, generallycylindrical body or housing 8, at the upper or outer end of which anexternal, radial, annular flange 9 is provided for supporting aninternal, annular valve seat 10. A flange ll, overlying andcomplementary to the flange 9, is formed at the upper or outer end ofthe valve seat 10 which has an annular,'beveled, internal seating face12 at its lower or inner margin and which, preferably, has an internal,outwardly-flaring and beveled surface 13 at its upper or outer endportion. For connecting the check valve to the control valve, aninternal, annular recess 14 is provided in the lower or inner end of thenipple 6 for receiving the nested flanges 9 and II on the upper or outerends of the check valve housing 8 and valve seat. As shown at 15, thelower or inner extremity of the nipple is crimped or pinched radiallyinward so as to underlie and confine the flanges. It is noted, however,that the check valve 7 may be secured to the control valve or in thecollar 2 or tank opening 3 in any suitable manner.

lmmediately below or inwardly of the valve seat 10, a plurality,preferably a trio, of identical, coplanar, circumferentially-extendingslots or elongate ports 16 (FIG. 5) is formed in the tubular upper orouter portion or wall 17 of the check valve housing for establishingcommunication between the exterior of said housing and its bore 18.Preferably, the ports 16 are of maximum length and minimum quantity,being spaced equally by narrow, upright partitions or posts 19, so as toprovide maximum flow areas within practicable limits. A tubular nippleor collar 20, of relatively small diameter, is provided at the lower orinner extremity of the housing 8 and is connected to the upper or outerportion or wall 17 thereof by a plurality of equally-spaced, upright,elongate members or legs 21 of narrow width. Preferably, the legs 21 arein alignment with the posts 19 so as to be of the same minimum quantityand function as a valve cage having flow passages, spaces or ports 22,of large or maximum area, therebetween. Each of the valve cage legs hasan upwardly, outwardly inclined lower or inner portion 23, an elongate,upright intermediate portion 24 offset inwardly of the wall 17 of thehousing, a transverse or horizontal portion 25 projecting radiallyoutward of the upper or outer end of the intermediate portion, and anupper or outer portion 26 which is alined with said housing wall so asto form an extension thereof. Obviously, the transverse leg portions 25provide upwardly or outwardly facing, internal shoulders.

An elongate, complementary valve stem 27 extends slidably through thecollar 20 ofthe housing 8 (FIGS. 2-4) and has an annular spring follower28, of larger internal diameter, mounted on its lower or inner end by acoacting groove 29 and snap ring 30. As shown at 31, the upper or outerend portion of the follower 28 is of reduced internal and externaldiameters to provide an upwardly or outwardly facing, external, radialshoulder for confining the lower or inner end of a helical compressionspring 32 which has its upper or outer end surrounding the housingcollar and bearing against the lower or inner leg portions 23 wherebythe valve stem 27 is constantly urged downwardly or inwardly. Forsupporting a circular valve element or disk 33 within the cage formed bythe legs 21, the valve stem has an upper or outer portion or shank 34 ofreduced diameter to provide an upwardly or outwardly facing radialshoulder.

A guide member or spider 35 is confined upon the reduced shank 34, aboveor outwardly of and resting on or engaging the valve disk 33, byupsetting the upper or outer extremity 36 of said shank and has aplurality, preferably a trio, of upright, radial wings 37. The valvedisk is of sufficient diameter to have a sliding fit within and beguided by the complementary internal surfaces of the intermediate legportions 24. An annular, beveled seating face 38 is provided at theupper or outer margin of the disk 33 which, preferably, has a relievedlower or inner margin 39 so as to minimize flow turbulence therearoundas well as facilitate downward or inward movement of said disk relativeto the cage legs 21.

The guide spider 35 is adapted to slidably confine a tubular valvemember or sleeve valve 40 which has an internal, radial flange 41 forengaging downwardly or inwardly facing shoulders 42 formed on the wings37 of said spider by reducing the width ofthc lower or inner portions ofsaid wings. An external, annular, beveled seating face 43 is provided atthe upper or outer end of the sleeve valve 40 for complementaryengagement with the lower or inner face 13 of the valve seat 10. Thesleeve valve is of sufficient diameter to rest upon the internalmarginal portions of the radial shoulders formed by the transverse legportions 25 so as to be spaced an appreciable distance from the wall 17of the valve housing 8 and thereby facilitate flow around the exteriorof said sleeve valve.

Due to the force of the compression spring 32, the guide spider isconstantly urged downwardly or inwardly to hold the shoulders 42 of itswings engaged with the flange 41 of the sleeve valve and said flangeengaged with the radial shoulders of the legs 21. An internal. annular,beveled face 44 is provided at the lower or inner end of the internalflange of the sleeve valve for seating engagement with the face 38 ofthe valve disk 33. Since the guide spider is reciprocal with the valvestem 27 and valve disk relative to the sleeve valve 40 as well as thevalve seat, manifestly, it is desirable to relieve the upper or outerand lower or inner external margins of each of the wings 37 as shown at45 and 46.

When fluid is withdrawn from the tank 1, it flows upwardly or outwardlythrough the dip tube 4, excess flow check valve 7 and manual controlvalve 5. At normal withdrawal rates, the force of the compression spring32 is sufficient to prevent the pressure drop across the valve disk 33from lifting said seat whereby said spring maintains the check valve inits open position with said-valve disk intermediate the ends of thevalve cage legs 21 and ports 22 as shown in FIGS. 1 and 2. ln additionto flowing around the valve cage legs and through the large portsintothe bore 18 of the check valve housing 8 between the wings 37 of theguide spider 35 as well as around the valve sleeve 40, the fluid enterssaid bore through the slots 16 of the housing wall 17. Since these slotsare upwardly or outwardly of the valve disk 33, it is readily apparentthat the portion of the effluent fluid flowing through said slots has noeffect upon said valve disk.

It is noted that the large ports and slots coact with each other as wellas the guide wings and valve sleeve to divide the outflow, as well asinflow, into smaller, separate streams and control the size and effectof the efflux area of the check valve 7 as well as to substantiallyeliminate or greatly reduce the undesirable effect of the relativelyrestricted area of the dip tube upon the closing characteristics of saidvalve. Due to the large area of the ports 22, both longitudinally andcircumfcrentially of the valve housing 8, the lower or inner portion ofthe flow passage formed by the bore 18 of said housing is in directlateral as well as axial communication with the flow space exteriorly ofsaid housing so as to reduce restriction of flow.

It is conventional to vary the strength of the compression spring inaccordance with the desired rate of withdrawal of the fluid in gallonsor cubic feet per minute. When the withdrawal rate exceeds thepredetermined quantity, the pressure drop across the valve disk andsleeve valve overcomes the force of the spring 32 and compresses saidspring so as to close the excess flow check valve. As shown in FIG. 3,the valve disk 33 and sleeve valve 40 move upwardly or outwardly of thetank 1 simultaneously with the valve stem 27 until the upper or outerface 43 of said sleeve valve seats against the lower or inner face 13 ofthe valve seat 10 due to the axial space between said complementaryfaces being less than the axial space between the complementary seatingfaces 38 and 44. Consequently, the valve disk continues to move upwardlyor outwardly relative to the sleeve valve so as to seatingly engage thelatter faces, this engagement holding the faces 13 and 43 in engagement.Usually, a minute vent opening (not shown) is provided in the sleevevalve to bleed off excessive pressure and facilitate subsequent openingof the check valve 7 after closing thereof.

Since the excess flow check valve is mounted at the lower or inner endof the control valve 5 so as to depend into the dip tube, it isprotected from damage and prevents outflow in the event that saidcontrol valve is broken off or otherwise rendered inoperative. When inopen position, the excess flow check valve has a low pressure dropacross its valve disk and sleeve valve during withdrawal as well asfilling so as to accommodate maximum flow. Due to the construction ofthe check valve 7, its moment of closing is substantially unaffected byvariations in its mounting and said valve closes at substantially thesame pressure drop irrespective of whether it is disposed within a diptube or within the open vapor space of a storage tank which does nothave a dip tube and regardless of the construction and size of the diptube. The two-stage closing of the excess flow check valve provided bythe sleeve valve and valve disk is of major importance in that lessforce is required for such closing whereby a compression springoflcssstrength as well as greater sensitivity and resiliency can be utilized.

As stated hereinbefore, the ports 22 are of minimum quantity and ofmaximum dimensions longitudinally and circumferentially of the valvehousing 8 so as to expose substantially all of the valvedisk 33 to theexterior of said housing substantially throughout the travel of saidvalve disk. It has been found that the separate formation andlongitudinal spacing of the slots 16 from the ports are most desirablesince the wall 17 of the valve housing is of sufficient circumferentialarea to partially shield the valve sleeve 40 throughout its travel fromdirect lateral exposure to the housing exterior and thereby prevent theclosing characteristics of the check valve from being varied appreciablyby the relatively restricted area of the dip tube 4.

It is noted, however, that the closing of the check valve 7 is lessresponsive than the closing of conventional check valves to variationsin the flow space area exteriorly of the valve housing even when itswall is substantially eliminated as shown in FIG. 7 wherein a slightlymodified embodiment of the invention is illustrated. This check valve 50may be identical to the valve 7, except for the slots 16, legs 21 andports 22 of the latter, and has longer legs 51 extending outwardly orupwardly past the valve disk to a point immediately inward of the outer,or below the upper, end or the valve, Due to the extended length of thelegs 51, larger ports 52 are formed and are of greater longitudinaldimension so as to have an area equal to the combined areas of the slots16 and ports 22 and the major portion of the valve housing wall 17.Although the larger ports 52 provide a greater flow area, the absence ofmost of the housing wall renders the modified valve 50 more responsiveto variations in the exterior flow space whereby said valve is not asversatile as the check valve 7.

lclaim:

1. An excess flow check valve including:

a generally cylindrical housing having a therethrough;

an annular valve seat at one end of the passage;

internal shoulder means in said passage spaced from the valve seat;

a valve stem extending coaxially ofsaid passage;

a valve element carried by the valve stem;

a tubular valve member movable in said passage between the shouldermeans and valve seat relative to the valve element and valve stem;

means loosely connecting the tubular valve member to said valve stem inspaced relation to the valve element to limit relative movement ofsaidvalve member;

said tubular valve member having a seating face complementary to saidvalve seat for engagement therewith and an opposed seating face forcomplementary engagement with said valve element;

resilient means carried by said valve stem for urging said valve elementaway from said valve member and said member away from said valve seat;

the housing having a plurality of lateral port means of relatively largearea and minimum quantity for separating the flow between the exteriorof said housing and its passage into smaller streams of sufficient areato minimize turbupassage lencc and provide substantially uniform closingof the valve irrespective of the exterior flow area; and

the relatively large area and minimum quantity of the plurality oflateral port means exposing substantially all of said valve element andat least a portion of said valve member directly to the exterior of saidhousing.

2. An excess flow check valve as defined in claim 1 wherein theplurality of lateral port means includes:

a first portion elongated circumferentially of the valve housing betweenthe valve seat and tubular valve member in its unseated position; and

a separate second portion spaced from the first portion innonoverlapping relationship and of maximum dimensions longitudinally andcircumferentially of said valve housing so as to be substantiallycoextensive with the travel of the valve element.

3. An excess flow check valve as defined in claim 2 wherein the tubularvalve member is closer to the valve seat than to the valve elementwhereby said valve member engages said valve seat before said valveelement engages said member upon closing of the valve.

4. An excess flow check valve as defined in claim 2 wherein the valvehousing is spaced laterally from the tubular valve member to provide aflow space there-between.

5. An excess flow check valve as defined in claim 2 wherein theplurality of lateral port means is formed by a plurality of narrow legsextending longitudinally of thevalve housing.

6. An excessflow check valve as defined in claim I wherein the tubularvalve member is closer to the valve seat than to the valve elementwhereby said valve member engages said valve seat before said valveelement engages said member upon closing ofthe valve.

7. An excess flow check valve as defined in claim 6 wherein the valvehousing is spaced laterally from the tubular valve member to provide aflow space therebetween.

8. An excess flow check valve as defined in claim 6 wherein theplurality of lateral port means is formed by a plurality of narrow legsextending longitudinally of the valve housing.

9. An excess flow check valve as defined in claim 6 wherein theplurality of lateral port means is continuous and substantiallycoextensive with the length of the valve housing from the valve seat tothe opposite end of said housing.

10. An excess flow check valve as defined in claim I wherein the valvehousing is spaced laterally from the tubular valve member to provide aflow space therebetween.

11. An excess flow check valve as defined in claim- 1 wherein theplurality of lateral port means is formed by a plurality of narrow legsextending longitudinally of the valve housing.

12. An excess flow check valve as defined in claim ll wherein the valvehousing is spaced laterally from the tubular valve member to provide aflow space therehetween.

13. An excess flow check valve as defined in claim 1 wherein theplurality of lateral port means is continuous and substantiallycoextensive with the length of the valve housing from the valve seat tothe opposite end ofsaid housing.

14. An excess flow check valve as defined in claim 13 wherein the valvehousing is spaced laterally from the tubular valve member to provide aflow space therebetween.

15. An excess flow check valve as defined in claim 13 wherein theplurality of lateral port means is formed by a plurality of narrow legsextending longitudinally of the valve housing.

